POF-MIP-SPR Sensor for Analyte Detection

The SPR determinations were made by the D-shaped POF-MIP-SPR sensor. The experimental setup consists of a halogen lamp (HL–2000–LL, Ocean Optics, Dunedin, FL, USA) illuminating the SPR-POF-MIP sensor and a spectrum analyzer (USB2000+UV–VIS spectrometer, Ocean Optics) connected to a computer. The spectral emission of the lamp ranges from 360 nm to 1700 nm and the measurements were performed from 300 nm to 1050 nm. Measurements were performed by dropping a small volume, usually 40 μL, of the appropriate solution on the platform and incubating for 5 min. The light transmission spectrum was obtained. The spectra were normalized to the transmission spectrum obtained at the same platform, before the MIP deposition (bare platform), in the air, since in this dielectric not any plasmon resonance is expected to take place due to the low RI of air [11 (link)]. The transmission minimum corresponds to the resonance wavelength The signal is given by the variation of the resonance wavelength (Δλ, nm) with respect to the resonance wavelength of the blank solution, due to the refractive index variation of the polymeric layer upon the combination of the substrate.